Just FYI, I once tested the time to warm my little engine (1.0L) with the OEM 300 watt heater vs. an inline 800w coolant heater:

300 watt heater:

800 watt heater:

Note my 300w OEM heater isn't really comparable to the Micra's. The Micra's is likely (hopefully) a more effective frost plug installation (in the water jacket), where the Firefly's is an externally mounted heating element bolted to the block below the intake manifold.

So you can see in my case it doesn't make much sense to plug in for more than an hour and a half, whether using 300 or 800 watts. At that point, heat loss equals heat input and I'm just wasting electricity.

I'm using mine but not all the time yet. Just rhe cold minus ten days and when we got blasted with a foot of snow. The micra block heater works so well it melts snow on the hood. I put synthetic oil in mine so I will use it more for clearing the Windows faster than for keeping my oil flowing. Mine has a metal clip on the cord with a hole in it where does that go? What's the proper routing? I have done through the grill, out the hood opening and out the bottom but none seemed right.

Lower grille has bigger openings than the upper grille, but if you did the condenser coil protection as I did, it might just need to come out either through the hood or just under the bottom of the bumper.

In our culture obsessed with absurd excess, the Nissan Micra is my counterculture car of choice.
Be sure to visit my blog at mymicra.com!

Well tonight will be a block heater night in my neck of the woods. The heater cord has a clip on it and its meant to go somewhere I just haven't found it yet.I am off on Wednesdays so I will take a real look then as every time I use the thing its dark and cold.